Network users often desire to add an additional router to a network already configured with an existing router. For example, a user may wish to take advantage of new technology features such as VoIP. Because the existing router may have a desired feature such an embedded modem and since it is already configured for the network, the user may be reluctant to remove the existing router. A typical user lacks the technical expertise necessary to configure the new router into a mode of operation that is compatible with the existing router. For example, the existing router may be performing a network address translation (NAT) function. By employing NAT, the existing router allows multiple clients to share a public IP address. In particular, this sharing is often implemented using a form of NAT known as network address port translation (NAPT). The following discussion will simply refer to the various forms of address translations as NAT/NAPT. Conflicts arise when the newly-added router also employs NAT/NAPT, thereby creating what may be denoted as a double-NAT network. For example, to install a new router into an existing network, a user may couple a wide area network (WAN) port of the newly-added router to a local area network (LAN) port for the existing router. Peer-to-peer applications such as instant messaging or Internet gaming running behind the newly-added NAT/NAPT device may not operate normally due to the double translation of addresses that occur in a double-NAT network. In addition, dynamic host configuration protocol (DHCP) conflicts may arise. If the routers are on different subnets, roaming problems may occur. Moreover, it is difficult to configure the newly-added router from a computer coupled to the existing router because the newly-added router has an unknown IP address assigned to it from the DHCP server in the existing router. In addition, the upstream quality of service (QoS) for the newly-added router will be limited by the QoS capabilities of the (presumably older) existing router.
To prevent some of the problems associated with a double-NAT network in which the newly-added router couples through its WAN port to a LAN port of the existing router, a user may refrain from coupling devices to LAN ports on the newly-added router. In this fashion, the user may take advantages of new technology offered by the new router such as VoIP while keeping the already-configured-for-the-network existing router. Such a configuration eliminates the application and roaming problems caused by the presence of a double-NAT network. However, the QoS limitations and difficulties in configuring the newly-added router from a computer coupled to the existing router remain. Moreover, preventing attachment to the LAN ports on the newly-added router may violate a user's expectations. Thus, a user may also configure the newly-added router to disable its NAT and its DHCP server to allow the attachment of devices to the LAN ports. However, the difficulty of configuring the new router from a computer coupled to the existing router remains. Furthermore, the devices attached to the LAN ports of the new router may still be on a separate IP subnet as the new router is still acting as a layer 3 forwarding service (routing).
In an alternative implementation, a user may have the newly-adder router couple through its LAN port to a LAN port of the existing router. The newly-added router would then be configured by the user to have its DHCP server disabled such that the newly-added router acts as a switch for the existing router. However, this implementation would be inappropriate for routers such as VoIP-enabled routers—a VoIP-enabled router often has its VoIP port on the WAN side, not the LAN side such that by coupling the newly-added router through its LAN port, the VoIP capability is bypassed. Moreover, if the newly-added router has the same IP address as the existing router, configuration difficulties are unabated. Finally, the configuration difficulties may also be exacerbated if the existing router and newly-added routers are in different subnets.
Rather than install the newly-added router downstream from the existing router as discussed above, the new router may be installed in an upstream location such that it resides between the modem and the existing router. However, the double NAT problems would thus be transferred to the existing router. Moreover, users then have the difficulty of disconnecting existing network cables for reconnection to the newly-added router. In addition, it is difficult for users to transfer existing configuration settings such as WAN PPPoE usernames and passwords from the existing router to the new router. Also, such a configuration makes reconfiguring the existing router or accessing the GUI of either router problematic. Finally, this approach is inapplicable if the existing router is a gateway device having an embedded modem.
Accordingly, there is a need in the art for improved routers that avoid double NAT issues and other problems associated with their integration into existing networks.